What is the deal with the huge sticks they are walking around with? And I like how they keep bringing in more fat dudes to get punched in the gut!

The systema place where I briefly trained was in an aikido dojo, so there were plenty of jo around. Anyway, the sticks were used for drilling, but also for Russian massage. One person lies on the ground while the other person basically walks around on top of them, using the stick to ground some of the weight and to stabilize (systema practitioners being a rather uneven surface).